COLLOQ 1 Flashcards
(35 cards)
What is nuclear medicine?
Is the application of radionuclides (RN) for the purpose of:
> m. DIAGNOSIS (radionuclide diagnosis RND)
> RADIOTHERPAY (RT)
-metabolic brachytherapy (use of short range radio source to treat tumors)
What radioactivity?
spontantenous change of mass, electrical charge or energy of atomic nucleus with the emission of a, b or g emissions
What are the types of ionising radiation?
> direct ionising radiation
> indirect ionising radiation
Give examples of direct and indirect ionising radiation?
> direct IR - alpha + beta
> indirect IR - gamma + roentgen
What is a radionuclide?
Elements whose nuclei has the ability to decay - emitting ionising/ radioactive rays
Give examples of RN particulates ?
> beta electrons
beta positrons
alpha
Give examples of RN electromagnetic/ photon rays
> gamma rays
Outline the main elements of radioactive families?
> thorium
uranium
actinium
neuptinium
What is the penetrating ability of alpha, beta and gamma?
alpha + beta = short penetration
gamma = deep penetration
What is absorbed dose?
measure of the energy deposited in matter by ionizing radiation per unit mass
> units: Gray (Gy)
What does the biological effect of IR depend on?
> DOSE
How does DOSE affect the biological effect of IR?
> higher the dose»_space; greater the damage effect on living tissue
How does IR work in RT (radiotherapy) ?
> IR damages DNA of exposed tissues ( cancer + normal cells)»_space; leading to cellular death
What is the ALARA principle?
1) the radiation dose received by P must be ALARA
As Low As possible/ Reasonably Achievable
2) the ratio of risk vs benefit should be kept ALARA
As Low As possible/ Reasonably Achievable
Outline the uses of electromagnetic rays and particulate rays?
> electromagnetic rays (Y)
- long range
- deep penetration
- detected outside body
- low energy
- low dose
- RND radio nuclear diagnosis
> particulate rays (a + b)
- short range
- short penetration
- not detected outside body
- so not useful for RND
- high dose
- RT (metabolic brachytherapy)
What is the RN emission for Iodine 131?
> both Y and b-
Y = RND
b- = RT
What is the RN emission for Technetium (Tc) 99?
> pure Y emission
> for RND
What is the RN emission for Fluorine 18 + Gallium 68?
> b positron
pairs of annihilation Y photons
PET scans (Positron emission tomography)
Define pharmaceuticals?
chemical compounds with selective accumulations/ uptake by certain organs/ tissues
What specific compounds are used for bone metabolism and thyroid metabolism?
> bone - phosphates
> thyroid - iodine
Outline Radiopharmaceuticals (RPh) for bone specific?
> Ca-P metabolism
accumulate in bones
Tc 99 -Phosphate compounds
Outline RPh for Thyroid specific?
> thyroid hormone production
Ionine (NaI)
99 Tc-eluate
Outline RPh for tumor specific ?
> accumulate in malignant tumors
99 Tc -MIBI
18 F -FDG
How does NM diagnostic devices work?
> Y rays emitted by RN incorporated in RPh
> detected from outside body by NM diagnostic devices
